load or no load to tune g320x?

Hi, ive been running 3 g320x's on my mill, and if i jog the machine any faster than about 14-15ipm, the drives will fault out. im assuming this is because the drives are over traveling when they come to a stop, which is exceeding the "out of position" limit on the drives. i tuned them the best i could with an oscilloscope, but couldnt seem to get them PERFECT, so i got the "good enough" and have been running with it. as mentioned, anything under 14-15 ipm and they run fine. so my question is, should i tune the motors connected to the machine while tuning them? or should they be tuned separated from the load? Or could it even be an issue with not supplying the correct amperage to the drives via the trimpots? hope to hear what you guys think. thanks
-Cody